Multiplication Calculations - Stage 1

Children will experience equal groups of objects. They will count in 2s and 10s and begin to count in 5s. They will work on practical problem solving activities involving equal sets or groups.

Stage 2

Children will experience equal groups of objects. They will count in 2s and 10s and begin to count in 5s. They will work on practical problem solving activities involving equal sets or groups. They will also begin to use arrays with the support of the teacher.

Stage 3

Children will develop their understanding of multiplication and use jottings to support calculation:

Repeated addition

3 times 5 is 5 + 5 + 5 = 15 or 3 lots of 5 or 5 x 3

Repeated addition can be shown easily on a number line :

and on a bead bar :

Commutativity

Children should know that 3 x 5 has the same answer as 5 x 3. This can also be shown on the number line.

Arrays

Children should be able to model a multiplication calculation using an array. This knowledge will support with the development of the grid method.

Stage 4

Children will continue to use

Repeated addition

4 times 6 is 6 + 6 + 6 + 6 = 24 or 4 lots of 6 or 6 x 4

Children should use number lines or bead bars to support their understanding.

Arrays

Children should be able to model a multiplication calculation using an array. This knowledge will support with the development of the grid method.

Scaling

e.g. Find a ribbon that is 4 times as long as the blue ribbon.

Using symbols to stand for unknown numbers to complete equations using inverse operations.

Partitioning

38 x 5 = (30 x 5) + (8 x 5)

= 150 + 40

= 190

Stage 5

Children will continue to use arrays where appropriate leading into the grid method of multiplication.

Grid Method

TU x U

(Short multiplication - multiplication by a single digit)

23 x 8

Children will approximate first

23 x 8 is approximately 25 x 8 = 200

Stage 6

Grid Method

HTU x U

(Short multiplication - multiplication by a single digit)

346 x 9

Children will approximate first

346 x 9 is approximately 350 x 10 = 3500

TU x TU

(Long multiplication - multiplication by more than a single digit)

72 x 38

Children will approximate first

72 x 38 is approximately 70 x 40 = 2800

Using similar methods, they will be able to multiply decimals with one decimal place by a single digit number, approximating first. They should know that the decimal points line up under each other.

e.g. 4.9 x 3

Children will approximate first

4.9 x 3 is approximately 5 x 3 = 15

Stage 7

ThHTU x U

(Short multiplication - multiplication by a single digit)

4346 x 8

Children will approximate first

4346 x 8 is approximately 4346 x 10 = 43460

HTU x TU

(Long multiplication - multiplication by more than a single digit)

372 x 24

Children will approximate first

372 x 24 is approximately 400 x 25 = 10000

Using similar methods, they will be able to multiply decimals with up to two decimal places by a single digit number and then two digit numbers, approximating first. They should know that the decimal points line up under each other.